Methods of conducting an environmental test

ABSTRACT

Methods for sampling the particulates and substances emitted from a test sample when the surface of the sample is ablated. The disclosed sampling chamber and methods avoids the need for clean rooms and other expensive testing apparatus and can be used to test a variety of materials in accordance with standard measurement procedures. Use of the testing chamber and methods assists with safety and risk evaluation in applications such as painting and removal of coatings.

CROSS REFERENCE TO OTHER PATENT APPLICATIONS

The present application is a Divisional of U.S. patent application Ser.No. 16/873,796, which was filed on Jul. 8, 2020, and claims the benefitof U.S. Provisional Patent Application Ser. No. 62/921,998 filed 19 Jul.2019 and titled: Environmental Sampling Chamber, the entirety of eachare incorporated herein by reference.

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

BACKGROUND

Removing coatings or the top large layer of materials from surfaces canresult in particulates becoming airborne and being inhaled by workers orother personnel or bystanders. This situation most commonly occurs whenremoving a coating or paint from a surface via scrapping or othermechanical means but can also occur via erosion and exposure when thesurface is exposed to the elements. Depending upon the method of surfaceremoval, chemical reactions can also occur which may alter the chemicalcomposition of the particulates created as the coating or surfacematerial is separated from the underlying substrate material. For eachof these reasons, environmental safety and hazard analysis are conductedto determine and better understand the particulates, carcinogens,biohazards, or gases released as the coating or surface layer isremoved. These tests assist in identifying any health and safety risksarising from contact with or inhaling the released particulates orgasses; and to define exposure limits and any personal protective gearrequired.

In industry, such tests are sometimes conducted in large environmentalclean rooms. Clean rooms are expensive to use and operate. Large cleanrooms require operators to use specialized full body personal protectiveequipment ablating or removing the top surface coating in the clean roomenvironment introduces an excessive amount of airborne contaminants intothe clean room environment. Such tests are therefore costly andimpractical to conduct in such settings. Returning a clean room to cleanstatus after a test requires large amounts of neutralizing solution andcleaners after each use or test run.

For these reasons, industry has sought smaller self-contained testdevices. FIG. 1 shows a side view of a prior art collection vessel 2.Prior art collection vessel 2 bears resemblance to a standing cylinderin which a test sample 4 is mounted on a plate fixed to a base 8. Anablation tool 10, which can be for example a laser, sends a beam ofdirected energy 12 through lens 14 directed at sample 4. The distanceand energy of ablation tool 10 is fixed by the optics of lens 14 and thefixed distance of test sample 4 from lens 4.

As shown in FIG. 2 , air circulates through vessel 2 as supplied bycirculation pump 18 via input port 20 and exit port 22. When directedenergy beam 12 hits test sample 4, the beam ablates the sample 4generating particulates which become airborne within the interior volumeof vessel 2. A sample collector filter 24 catches the airborneparticulates ablated off test sample 4. The material collected in filter24 can then be analyzed according to industry best practices andanalysis protocols. One such Standard Operating Procedure is AirSampling for Metals, published by Scientific, Engineering, Response andAnalytical Services, SERAS, SOP 2119, Rev 1.1. The entire text of whichis incorporate herein by reference.

In prior art devices, only two ports 20 and 22 are provided. Thislimitation can adversely impact the circulation and flow such that bestpractices for the collecting and analyzing byproducts may not be met. Inparticular, the prior-art collection device of FIGS. 1 and 2 clogseasily and does not support industry standard guidelines or bestpractices for collecting diluted or concentrated samples.

In addition, the collection vessel does not allow for adjustment of theablation tools in relation to the test sample and optical windowcombination. If this combination fails to focus enough energy on thetest sample, the amount of time necessary to run a test is extended.Increasing the time necessary for a test increases costs. Failure tofocus enough energy may possibly not be reflective of the actual removalpractice in the field.

Increasing the energy focus on the sample by moving the ablation toolcloser to the test vessel 2 is impractical. If the ablation tool movesforward closer to the test sample test vessel 2, damage to vessel 2 ispotentially catastrophic. The fixed position of the test sample in theprior art device; FIGS. 1 and 2 relative to the optical window thuslimits the numbers of useful test configurations and hence the numberand types of materials and levels of energy that can be tested. Toolstoo close or too far away from the test sample adversely impact the testprocedure, test results, and the possibility the device will experienceclogs.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure includes recognition of the problems andlimitations of prior art devices. The environmental chamber of thepresent disclosure is easily adjustable, self-contained, andconfigurable. According to one aspect of the disclosure theenvironmental chamber can be configured into multiple lengths to bettermanage circulation within the test chamber and to manage the amount ofenergy directed at the test sample. Attaching chambers togetherincreases the total distance between the test sample and the ablationtool and reduces the possibility of damage to the chamber.

According to another aspect of the disclosure, the environmental chamberincludes multiple inlet/outlet ports. Multiple ports manages aircirculation and assists in the prevention of clogs. The EnvironmentalProtection Agency (EPA) has documented a potential problem with thesampling method of the prior art due to particulate overloading thefilter. In one embodiment of the present disclosure, the disclosureprovides an expansion capability for additional ports by standardizingthe ends that connect to the main chamber body. Different end pieceswith different numbers of ports or other tools or interfaces may beattached. Reducing filter clogging and improving circulation parametersalso reduces the possibility of biased low results and produces a moreaccurate representation of the particulate and off gassing load likelyto occur under real world conditions.

According to other aspects and features of the present disclosure, thedisclosure reduces test costs and labor. Full body personal protectivegear is no longer a requirement since hazards are contained within thesealed environment of the test chamber. The configurable nature of thechamber easily enables one to meet different test condition requirementsand to accommodate different types of samples or sample material withoutdesigning or constructing a new test apparatus.

Further advantages and features of the present disclosure will bedescribed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side-view of a prior art collection vessel;

FIG. 2 is a schematic view of a test configuration illustrating theoperation of the prior art collection vessel of FIG. 1 ;

FIG. 3 is a side-view representation of an environmental chamberaccording to an embodiment of the present invention;

FIG. 4A is a side-view representation of an environmental chamberaccording to an embodiment of the invention highlighting a location andconstruction of a clamp assembly;

FIG. 4B is an exploded view of the clamp assembly highlighted in FIG. 4Aaccording to an embodiment of the present invention;

FIG. 5A is a side view of an environmental chamber according to anembodiment of the present invention showing a location and constructionof a second clamp;

FIG. 5B is an exploded view of the clamp located in the highlightedportion of FIG. 5A according to an embodiment of the present invention;

FIG. 6 is a schematic showing the environmental chamber of FIG. 3 in atest configuration according to an embodiment of the present invention;

FIG. 7 is a diagram of air flow during operation of an environmentalchamber according to an embodiment of the present invention;

FIGS. 8A and 8B are partial side-views of an environmental chamberaccording to an embodiment of the present invention, as well as theprior art test chamber of FIG. 1 illustrating differences in operationand results;

FIGS. 8C and 8D are partial, side-views of an environmental chamberaccording to an embodiment of the present invention, as well as theprior art test chamber of FIG. 1 , further illustrating differences indistance modifications and results;

FIGS. 8E and 8F are partial, side-views of an environmental chamberaccording to an embodiment of the present invention, as well as theprior art test chamber of FIG. 1 further illustrating differences indistance modification and results; and

FIGS. 8G and 8H are partial, side-views of an environmental chamberaccording to an embodiment of the present invention, as well as theprior art test chamber of FIG. 1 further illustrating differences inconfiguration and results.

Like reference numerals refer to similar elements or features throughoutthe drawings.

DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

FIG. 1 shows a side view of a prior art collection vessel 2. Prior artcollection vessel 2 bears resemblance to a standing cylinder in which atest sample 4 is mounted on a plates fixed to a base 8. An ablation tool10, which can be for example a laser, sends a beam of directed energy 12through lens 14 directed at sample 4. The distance and energy ofablation tool 10 is fixed by the optics of lens 14 and the fixeddistance of test sample 4 from lens 14.

When directed energy beam 12 hits test sample 4, the beam ablates thesample 4 thereby generating particulates, gasses, or other matter whichbecome airborne within the interior volume of vessel 2. As shown in FIG.2 , air circulates through vessel 2 as supplied by circulation pump 18via input port 20 and exit port 22. A sample collector filter 24 catchesthe airborne particulates ablated off test sample 4. The materialcollected in filter 24 can then be analyzed according to industry bestpractices and analysis protocols. In prior art devices, only two ports20 and 22 are provided. This limitation can adversely impact thecirculation and flow such that best practices for the collecting andanalyzing byproducts may not be met.

FIG. 3 shows an environmental chamber 100 according to an embodiment ofthe present invention, which is comprised of glass in a long cylindricalshape. A number of suitable materials, known to those of skill in theart, may also be used to construct the cylindrical body of chamber 100.Glass has several advantageous properties including clarity,non-conductivity, chemically safety and stability, ease of manufacture,and availability.

Chamber 100 may optionally be formed by joining multiple cylinderstogether to form a larger, more elongated, tube. These sections may bejoined by a variety of means known to those of skill in the art. FIG. 3shows sections joined together using a fusion weld 105.

Chamber 100 is further constructed to include an optical window 120.Optical window 120 attaches to environmental chamber 100 via a clampingmechanism. Optical window 120 allows directional energy emitted fromablation tool no to pass and be directed onto the test sample. Opticalwindow 120 is preferably fabricated to minimize imperfections whichcould reduce energy absorption and interfere with beam transmission asthe energy passes through window 120 and into chamber 100.

Chamber 100 further includes an inlet/outlet ports 135 and 151 formed aspart of the glass body of chamber 100. Ports 135 and 151 further includea threaded connection for mating with flexible tubing such as, forexample, a hose. Another clamping mechanism 155, secures an endcap 16 o.Clamping mechanism 155 secures via bolts 156 and wingnuts 157 which canbe hand tightened. Endcap 16 o includes both inlet/outlet port 161 andinlet/outlet port 162 both of which have industry standard threads forinterconnection of hoses or other peripherals.

Interaction of directed energy 111 toward test sample 140 causespotentially hazardous byproduct to disperse, not escape, environmentalchamber 100. The location of test sample 140 is adjustable, within anychamber 100 configuration, through placement of movable test plateholder 141, which rests on the inside of environmental chamber 100.

FIGS. 4A and 4B show attachment 200 of optical window 120 in greaterdetail. Starting at one end of environmental chamber 100 is a protrudinglip 210, comprised of glass, on the outside edge, allowing varying itemsa place to clamp to, and includes a channel for gasket 220 to fit in.Optical window 120 rests against gasket 220 sealing one end ofenvironmental chamber 100. The majority of optical window 120 is visiblesince only the outer edge of optical window 120 fits a reinforcementbracket 230. Reinforcement bracket 230 is round in shape, includes acoating preventing damage to optical window, and extends enough to matewith protruding lip 210. Clamping mechanism 130 includes u-shaped clamp240, available in different materials, with three holes for evencompression, and compresses the furthest end towards environmentalchamber 100. An identical u-shaped clamp 241 fits around theenvironmental chamber 100 and catches protruding lip 210. Bolts 131 fitthrough holes on u-shape clamp 241 passing through u-shape clamp 240,where wingnuts 132 secure to bolts 131 keeping components in place. Handtightening prevents glass breakage.

FIGS. 5A and 5B show endcap attachment 30 o to environmental chamber100. Clamping mechanism 155 is similar to optical window attachment 200and works in the same fashion. A protruding lip 310, comprised of glassincludes, on the outside edge, a u-shaped clamp 320 which fits snuglyaround environmental chamber 100 and slides outward catching onprotruding lip 310. Protruding lip 310 allows varying items a place toclamp to, and includes a seating channel for gasket 330. Endcap 160rests against gasket 330 thus sealing the end of environmental chamber100 and extends enough to mate with protruding lip 310. U-shaped bracket340 fits around endcap 160, but catches the edge closest toenvironmental chamber 100. Three holes on u-shape clamp 340 match theorientation of u-shape clamp 320 through which bolts 156 pass. Bolts 156join u-shaped clamp 34 and u-shaped clamp 320 as shown. Wingnuts 157 arehand-tightened to secure bolts 156. Following the clamping procedureshown in any of FIGS. 4A-5B allows several sections of environmentalchamber 100 to be joined together, to achieve any possible length,optical window, or endcap configurations.

FIG. 6 shows the environmental test chamber of FIG. 3 in a testconfiguration and the interconnection of input/output ports: 135, 151,161, and 162 to circulation pump 400. Pump 400 is circulates any fluidmedium through environmental chamber 100, to carry matter ablated fromtest sample 140 for collection by filters 425 and 435 Pump 400 suppliesfluid to chamber 100 via inlet hose or tube 402 and couples to inletport 135 using a hose connector nut 401. Hose 402 secures to pump 400using a connector nut 408 coupled to circulation port 409.

Outlet port 151 uses a hose connector nut 411 to secure one end of hose412 to environmental chamber 100. A liquid backflow prevention 413,constructed via techniques well known to those skill in the art, couplesa solution apparatus 415 via nut 414. Solution apparatus 415 contains asolution for capturing gas or particulate matter for further testing.The composition of the solution varies according to the specific gas orchemical matter wished to be captured or likely to be contained in thematerials ablated from the sample. The composition of such solutions forcapturing particular gases and chemicals is well known to those of skillin the art.

Hose connector nut 416 attaches hose 417 to the opposing end of solutionapparatus 415. Hose 417 couples hose connector nut 418 to circulationport 419. Outlet port 162 also has a hose connection nut 421 to couplehose 422 to environmental chamber 100, while hose 422 slides onto oneend of a filter apparatus 425.

Filter apparatus 425 comprises an interchangeable fiber filter forcapturing variable size particulate matter at a micron level.Circulating fluid passes through filter 425 and through hose 427 whichcouples to circulation pump 400 using hose connector nut 428 atcirculation port 429. Outlet port 161 has a hose connection nut 431 thathose 432 to environmental chamber 100. The opposing end of hose 432slides onto one end of a filter apparatus 435. According to one possibleembodiment of the invention, fiber filter apparatus 435 comprises asecond type of fiber designed to capture a different micron sizeparticulate than fiber apparatus 425.

Circulating fluid passes through filter 435 and returns to circulatingpump 400 via hose 437 secured using a hose connector nut 438 tocirculation port 439. When all the aforesaid connections are made thesystem forms a closed loop of circulating fluid as diagramed in FIG. 7 .

FIGS. 8A through 8H compare environmental chamber 100 and prior artvessel 2 and show the concentration levels of directed energy 120 andthe resulting test samples results as a function of adjusting thedistance configuration of ablation tool no. In a first configurationshown in FIGS. 8A and 8B the optical windows in and 505 of each deviceboth sustain damage. The focus beam patterns 511 and 512 illustrate theconcentration of directed energy passing through the optical windows.This energy beam pattern causes the damage to the optical window in bothvessel 2 and chamber 100.

Directed energy beam 120 also has a narrow area of concentration on testsamples 140 and 506 as shown by patterns 516 and 517 respectively. Thisnarrows the concentration of energy on the test sample and can produceacceptable test results, but at the cost of damaging the optical window.

In the comparative example of FIGS. 8C and 8D, ablation tool no islocated at the second distance B nearer to the optical window than indistance A in this configuration, a wide dispersion of directed energy120 passes through optical window 111 preventing damage, as shown by thepass-through focus 521 pattern. In the prior art device 2 optical window505 also receives wide dispersion of directed energy 120 as shown inpass-through focus 522. Neither windows 111 nor 505 receive any damage.Both test sample plates 140 and 506 each receive a low concentration ofdirected energy 120 as shown in test focus 526 and 522. The directedenergy fails to interact properly with the test sample producing lessreliable test results. Thus, while the optical window is saved, thisconfiguration provides poor test data.

FIGS. 8E and 8F compare performances of environmental chamber 100 andprior art vessel 2 when ablation tool 110 is located closest toenvironmental chamber 100 at distance C. In this configuration, a widedispersion of directed energy 120 passes through optical windows in and505 as illustrated by focus patterns 531 and 532 respectively. However,the pattern 536 configurable positioning of test sample plate 140 allowssample 140 to be positioned such that energy 120 produces a mediumconcentration of which yields an accurate and reliable test process andresults. In contrast, in prior art vessel 2, directed energy 120 is oflow concentration at sample plate 506 as shown by in test focus pattern537. In the prior art device, no beneficial adjustment can be made byrelocating the test sample within the device and correspondingly poortest results are produced.

FIGS. 8G and H shows yet another comparative example betweenenvironmental chamber 100 and prior art vessel 2. In FIG. 8G a thirdclamp assembly 545 provides expansion of environmental chamber 100,increasing its overall length. With ablation tool no at distance D whichis of same or similar distance as distance C of PIG. SE, a widedispersion of directed energy 120 passes through optical window 111, asillustrated by pass-through focus 551 and 552. Test sample plate 140receives a high concentration of directed energy 120, shown by testfocus pattern 556, which results from the benefit of an adjustable testarea within the elongated tube of chamber 100. Prior art vessel 2 lacksthis configurable feature. Directed energy 110 is of low concentrationat sample plate 506. The test sample location cannot be adjusted totrain and concentrate the energy on sample 506 in such a manner as toproperly ablate the material and produce the most reliable test results.

The environmental test chamber of the present invention thus allows thedirected energy to be concentrated on the test sample in the manner bestable to produce reliable and trustworthy test results. The distance ofthe test sample from the energy source can be manipulated by moving thesample location within the chamber 100, with the desired position beinga function of the type of energy used and the characteristics of thematerial tested.

The range of positions at which the test sample can be located can befurther expanded by adding additional sections to make up chamber 100.Expanding the length of chamber 100 not only allows for additionalpositions for test sample 104 but can also facilitate management offluid circulation within the chamber. Managing the circulation withinthe chamber controls the turbidity of the flow and better management ofthe accuracy of test results. Managing the circulation and flow rateswithin the chamber also helps prevent clogging of the inlet and outletports.

Embodiments and advantages of the present invention have now beendescribed. The subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts are disclosed as example forms ofimplementing the claims. Many additional changes in the details,materials, steps and arrangement of parts, which have been hereindescribed and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principleand scope of the invention as expressed in the appended claims.

What is claimed is:
 1. A method for conducting an environmental test,comprising the steps of: placing a test sample on a test sample mount;securing the test sample mount within a hollow cylinder, the hollowcylinder comprising an elongated tube, wherein the hollow cylindercomprises a first and second section and a first clamp adapted to jointhe first and second section; securing, via a second clamp, a thirdsection of the hollow cylinder so that the elongated tube is extended,the second clamp adapted to removably couple the third section to thesecond section; pumping fluid into the hollow cylinder; directing a beamof energy at the test sample to remove matter from the test sample;extracting, via an exit port, the fluid from the hollow cylinder,wherein the exit port is located along the circumference of the hollowcylinder; and, collecting a sample of the matter by filtering the fluidas the fluid is extracted from the cylinder.
 2. The method of claim 1,further including the step of analyzing said sample of said matteraccording to a predetermined test criteria.
 3. The method of claim 2,wherein the step of analyzing said sample further includes the step ofidentifying a chemical composition of a particulate found in saidsample.
 4. The method of claim 1, wherein said fluid is air.
 5. Themethod of claim 1, wherein the step of directing energy comprisesdirecting a beam of energy from a laser.
 6. The method of claim 1, wherethe step of collecting a sample further includes the step of collectinga gaseous sample by passing said fluid through a solution.
 7. A methodfor conducting an environmental test, comprising the steps of: placing atest sample on a test sample mount; securing the test sample mountwithin a hollow cylinder of an environmental test apparatus, the hollowcylinder comprising an elongated tube, the hollow cylinder having afirst and second section and a first clamp adapted to join the first andsecond section; securing, via a second clamp, a third section of thehollow cylinder so that the elongated tube is extended, the second clampadapted to removably couple the third section to the second section;pumping fluid into the hollow cylinder via an input port; directing abeam of energy at the test sample through an optical window of thehollow cylinder, the beam adapted to remove matter from the test sample;extracting the fluid from the hollow cylinder via an exit port, whereinthe exit port is located along the circumference of the hollow cylinder;and, collecting a sample of the matter by filtering the fluid as thefluid is extracted from the hollow cylinder.
 8. The method of claim 7,wherein the test sample mount is moveable.
 9. The method of claim 7,wherein the test sample mount is adapted to be positioned at one of aplurality of distances from the optical window.
 10. The method of claim7, wherein the optical window is removable.
 11. The method of claim 7,wherein the input port is located on a top surface of the hollowcylinder and the exit port is located on a bottom surface of the hollowcylinder.
 12. The method of claim 7, wherein the optical windowcomprises a lens with a predetermined focal length.
 13. The method ofclaim 7, wherein the optical window comprises a transparent materialconfigured to diffuse energy transmitted from a source exterior to thehollow cylinder.
 14. The method of claim 7, wherein the hollow cylinderis composed of glass.
 15. A method for conducting an environmental test,comprising the steps of: mounting a test sample within a hollowcylinder, the hollow cylinder comprising an elongated tube, the hollowcylinder further comprising: an optical window, an input port, an exitport, a first and second section, and a first clamp adapted to join thefirst and second section; securing, via a second clamp, a third sectionof the hollow cylinder so that the elongated tube is extended, thesecond clamp adapted to removably couple the third section to the secondsection; pumping fluid into the hollow cylinder via the input port;receiving a beam of energy within the hollow cylinder via the opticalwindow, the beam adapted to remove matter from the test sample; and,collecting a sample of the removed matter via the exit port, wherein theexit port is located along the circumference of the hollow cylinder. 16.The method of claim 15, wherein the collecting step comprises extractingthe fluid from the hollow cylinder via the exit port and filtering theremoved matter from the extracted fluid.